The adhering state was previously studied by means of a general multipole-expansion-based singularity model for swimming microorganisms [1]}.
Both pushers and pullers were predicted to accumulate at an oil–water interface, giving rise to large density inhomogeneities in many-particle systems. The collective dynamics of microswimmers strongly affects their motion [2]}, [3]}.
They can exhibit highly organized movements with remarkable large-scale patterns, such as networks, complex vortices, or swarms. In the present work we analyse only a single swimmer. This might help to explain why we predict instead that only strong pushers can be trapped by an interface.
Li and Ardekani's work [4]} is probably the closest in methodology to work, although they studied the motion of microswimmers near a solid wall. They found that a swimmer that was initially oriented toward the wall can escape (bounce back) if the strength of its squirming is sufficiently weak.
However, they also reported another swimming mode, in which very strong swimmers (\(|\beta |>7\) ) were observed to repeatedly bounce at the wall, which we do not observe in our simulations of a soft interface, although a harder interface would be accessible within our methodology.
